A certain kind of snail can have a right-handed direction of shell coiling (DD or Dd) or left-handed coiling (dd). However, if direction of coiling is due to a protein deposited by the mother in the egg cytoplasm, then a Dd egg-producing snail and a dd sperm-producing snail will have offspring of which genotype(s) and phenotype(s)?
A) 1/2 Dd:1/2 dd; all right-coiling
B) all Dd; all right-coiling
C) 1/2 Dd: 1/2 dd; half right-coiling and half left-coiling
D) all Dd; half right-coiling and half left-coiling

Question

Quizplus · Accepted Answer

The offspring will have genotypes 1/2 Dd and 1/2 dd. However, since the direction of coiling is determined by the mother's genotype, all offspring will exhibit right-coiling due to the Dd mother's influence.

A Certain Kind of Snail Can Have a Right-Handed Direction